Inverted telephoto lenses having elements in edge contact

ABSTRACT

An inverse telephoto lens has a negative singlet widely spaced from a positive group of five lens elements, four of which may be at least in edge contact.

United Stat Morante INVERTED TELEPHOTO LENSES HAVING ELEMENTS IN EDGE CONTACT Robert J. Morante, Rochester, N.Y.

Bausch & Lomb Incorporated, Rochester, N.Y.

Dec. 20, 1971 Inventor:

Assignee:

Filed:

Appl. N0.:

US. Cl ..350/216, 350/178 int. Cl. ..G02b 9/60 Field of Search ..350/2 1 6 Jan. 30, 1973 [56] References Cited UNITED STATES PATENTS 2,922,337 1/1960 Glatzel ..350/216 X 2,983,191 5/1961 Lautenbacher ..3S0/2l6 3,467,464 9/1969 Ruehl ..350/216 Primary Examiner-John K. Corbin Att0rneyFrank C. Paraker et al.

[57] ABSTRACT An inverse telephoto lens has a negative singlet widely spaced from a positive group of five lens elements,

four of which may be at least in edge contact.

6 Claims, 1 Drawing Figure 3713724 NC) JR QLJSSIF amt-Hm museu- INVERTED TELEPIIOTO LENSES HAVING ELEMENTS IN EDGE CONTACT BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION The invention comprises a family of inverted telephoto lenses having five components and six elements. Since these lenses may be employed either as photographic lenses or as projection lenses the usual front and rear conjugate nomenclature is inapt, and therefore reference will be made herein to long and short conjugates, the long conjugate corresponding to the front conjugate when the lens is used as a photographic lens.

Thus, the lens has first a negative meniscus or planoconcave lens designated I on the long conjugate side, concave to the short conjugate side. It constitutes the negative portion of the inverted telephoto lens, and accordingly is rather widely airspaced from the first component of the positive group, biconvex lens 11. The remaining lenses may be at least in edge contact with one another and the first of them is positive meniscus lens 111 concave to the short side, preferably edge contacted with biconcave or plano-concave lens IV having its shallowest curvature preferably in edge contact with lens 111. The sharper curve of lens IV is preferably in edge contact with the fifth component, a doublet, of which lens V is a negative meniscus concave to the short side and in surface contact with lens VI which is biconvex.

The lenses in question feature a good freedom from distortion, image point displacement being held to no more than three percent, and good flatness of field.

DESCRIPTION OF THE DRAWING The drawing is an optical diagram illustrating the relative shapes, thicknesses and spaces of the components and elements of the lens of my invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The lens of my invention is represented in two prim ary designs A and B, design A being intended primarily as a photographic lens for use with a ph ototube and therefore having special corrections for green, red, and infrared light. Design B, on the other hand, is corrected in the visible ranges and is intended for use as a microprojection lens.

The construction data are set' forth in the following table wherein the numerals given are ratioed to the focal length of the lens, positive radii being taken as centered on the short conjugate side. The field half-angles respectively for lenses A and B are 25.6 and 22.5,

and their relative apertures are respectively fl2.8 and 1720.

As keyed to the drawing, and following customary lens design notation, the radii are identified by R, the element thicknesses by t, the element separations by S, the refractive indices measured on the Fraunhofer D lines by n and the Abbe numbers, or dispersion values, by 11, each with numerical subscript of sequential increasing value from the long conjugate toward the short.

TABLE Dis- B tances A B Glasses A B 2. 596 121 O. 135 O. 146 Hm I. 613 I. 613 0. 758 t7 0. 354 0. 250 11131 1. 697 1. 697 O. 961. 1.: 0. 177 O. 184 nm 1. 697 1. 697 3. 950 t1 0. 0. nm 1. 689 1. 689 0. 625 15 0. 100 0. 104 no; 1. 648 1. 648 1. 396 1:0 0. 199 0. 208 nm 1. 691 1. 691 31. 3 S1 0.366 0. 860 1 1 58. 6 58.6 0. 419 S2 0. (X18 0. 005 v1 55. 6 55. 6 1. 447 S5 0. 061 O. 042 v5 55. 6 55. 6 O. 512 S1 0. 057 0. 059 v1 31. 0 31. O 1. 578 v5 33. 8 33. 8 v0 54. 8 54. 8

While the designs A and B were made in response to certain specific performance goals for excellent performance with light input at certain particular frequencies, other designs whose data fall within the listed range of radii, thicknesses and spacings, and having glass types exhibiting refractive indices within 0.002 and dispersions within two units of those given, are thought to be capable of useful performances under perhaps restricted conditions.

Iclaim:

l. A five component inverted telephoto lens having a negative singlet airspaced from a five element positive group and having construction data within the following ranges:

2.500 5 11, 5 m 0.300 5 s1 5 0.000 0.032 5 R. 5 0. 750 0.0075 5 s- 5 0.0005 0.02. R. 5 0.001 0.042 5 01 5 0.001 1.708 5 -R. 5 3.050 0.057 5 s. 5 0.050 0.500 5 R5 5 0.025 1.011 1101 1.015 1.000 5 R11 5 1.300 1.005 11m 1.000 3.037 5 R1 5 31.3 1.005 001 1.000 0.410 5 R0 5 0.443 1.687 110. 1.001 1.100 5 R0 5 1.447 1.040 11135 1.050 0.443 5 R10 5 0.512 1.000 1101 1.00:1 0.988 5 R11 5 1.578 50.0 v1 00.0 0.135 5 t1 5 0.140 53.0 v1 57.0 0.250 5 t1 5 0.354 53.0 10 57.0 0.177 5 1, 5 0.104 20.0 1 1 33.0 0.120 5 t1 5 0.125 01.0 v.1 05.0 0100 5 t5 5 0.104 52.0 v11 50.0 0.100 5 t0 5 0.208 1 2. The lens of claim 1 having construction data sub stantially as follows:

R, 1 1, .135 1.013 R, .632 I, .354 n 1.697 R, .922 t, .177 71 1.697 R 1.798 1 .120 n 1.689 R, .580 t, .100 n 1.648 R. 1.006 I .199 71,, 1.691 -R, 3.037 S, .366 1;, 58.6 R. I .443 S, .008 1;, 55.6 R, 1.109 S, .061 1 55.6 R .443 S .057 11, 31.0 R, .988 1 33.8 7 54.8

3. The lens of claim 1 having construction data sub- R .5l2 's .059 1 3L0 stantially as follows: "Rn 1.578 n, 33.8 1 54.8.

B 2.596 1 .146 nu. 1.163 R, .758 t, .250 n 1.697 5 4. The lens of claim 1 having the third, fourth and 32: Z :3; 2" 1'22; fifth elements in edge contact with one another. D R, 625 1; .104 n 1.648 5. The lens of claim 2 having the third, fourth and 23 "1 fifth elements in edge contact with one another. 1 I 71 5 R. .419 S, .008 m 55.6 10 I 6. The lens of claim 3 having the third, fourth and R, 1.447 s .042 1,, 55.6 fifth elements m edge contact with one another. 

1. A five component inverted telephoto lens having a negative singlet airspaced from a five element positive group and having construction data within the following ranges:
 1. A five component inverted telephoto lens having a negative singlet airspaced from a five element positive group and having construction data within the following ranges:
 2. The lens of claim 1 having construction data substantially as follows: R1 Infinity t1 .135 nD1 1.613 R2 .632 t2 .354 nD2 1.697 R3 .922 t3 .177 nD3 1.697 -R4 1.798 t4 .120 nD4 1.689 R5.580t5 .100nD51.648 R61.006t6 .199 nD6 1.691 -R7 3.037 S1 .366 eta 1 58.6 R8 .443 S2 .008 eta 2 55.6 R9 1.109 S3 .061 eta 3 55.6 R10 .443 S4 .057 eta 4 31.0 -R11 .988 eta 5 33.8 eta 6 54.8
 3. The lens of claim 1 having construction data substantially as follows: R1 2.596 t1 .146 nD1 1.163 R2 .758 t2 .250 nD2 1.697 R3 .961 t3 .184 nD3 1.697 -R4 3.950 t4 .125 nD4 1.689 R5 .625 t5 .104 nD5 1.648 R6 1.396 t6 .208 nD6 1.691 -R7 31.3 S1 .860 eta 1 58.6 R8 .419 S2 .008 eta 2 55.6 R9 1.447 S3 .042 eta 3 55.6 R10 .512 S4 .059 eta 4 31.0 -R11 1.578 eta 5 33.8 eta 6 54.8.
 4. The lens of claim 1 having the third, fourth and fifth elements in edge contact with one another.
 5. The lens of claim 2 having the third, fourth and fifth elements in edge contact with one another. 